宽筛分颗粒高压热态最小流化速度的实验研究

Experiment study on minimum fluidization velocity in fluidized bed with wide particle size distribution at elevated pressure and high temperature

在内径80 mm的加压热态流化床实验台上,以4种不同平均粒径的宽筛分颗粒为实验物料,研究了在压力(0.1～4.5 MPa)和温度(20～800℃)范围内实验物料的最小流化速度。实验结果表明:在相同的温度下,最小流化速度随压力的增加而减小。而在相同的压力下,温度对最小流化速度的影响随床料的种类的不同而有明显的差别。基于Ergun方程和床层受力分析,得到了最小流化速度的计算式,给出了高温高压宽筛分颗粒流化床最小流化速度合理计算步骤,并与其他研究者的关联式和实验结果进行了对比,结果表明本文提出的预测方法与实验结果吻合较好,相对误差在10%以内,为增压流化床反应器的设计和运行提供较可靠的参考依据。

An experimental study of the influence of pressure and temperature on minimum fluidization velocity was carried out in a fluidized bed with an inner diameter of 80ram in the range of operating absolute pressure 0. 1 ~ 4. 5 MPa and temperature 20 ~ 800 ℃ with four wide particle-size distributions of different mean diameters. The results show that at a given temperature, minimum fluidization velocity decreases with increasing pressure and that at a given pressure, the effect of temperature on minimum fluidization velocity is dependent on the particle type. Based on Ergun equation and bed stress analysis, an equation about minimum fluidization velocity is proposed, and then reasonable calculation steps about it at elevated pressure and temperature is given. The discrete degree between predicted minimum fluid- ization velocity and experimental results is in the range of 10 %. Moreover, the accuracy of it is higher than the corre- lations often employed in literature. It seems that the conclusion is useful for the design and operation of the pressured fluidized bed.